FRACTIONATION STUDIES OF HUMAN ANTISERA CONTAINING LEUKOCYTE‐AGGLUTINATING AND CYTOTOXIC ISOANTIBODIES

Ten antisera from multiparous women or immunized volunteers containing isoantibodies to human leukocyte antigens were fractionated on Biogel P-300 polyacrylamide chromatographic columns. The fractions were tested by lymphocyte cytotoxicity and leukocyte agglutination and the IgG, IgM, and IgA levels of each fraction quantitated by the radial diffusion technique of Mancini (4) The following observations were made: (1) IgG in the absence of IgA and IgM had agglutinating activity. No cytotoxic activity was noted with these same levels of pure IgG. (2) IgM from some antisera in the absence of IgA and IgG agglutinated the cells from some but not all donors. The same level of IgM in these fractions failed to give a cytotoxic reaction. (3) The cytotoxic and agglutinating activity of other fraction pools could not be attributed to a single immunoglobulin since the fractions were not pure.